Stansted was placed on "lockdown", according to eyewitnesses (Image: PA)

The passengers are escorted off the jet after its emergency landing (Image: PA)

“The aircraft was safely escorted to Stansted Airport. The Typhoon aircraft were authorised to transit at supersonic speed for operational reasons; any inconvenience caused to local residents is regretted.”

A Ryanair spokesman said: “This flight from Kaunas to London Luton diverted to London Stansted in line with procedures after Lithuanian authorities received a suspected hoax security alert.